Conventionally, there is known a spark ignition type internal combustion engine that allows an electric field created in a combustion chamber to react with a spark discharge by an ignition plug and generates plasma, thereby igniting fuel air mixture. This type of an internal combustion engine allows the spark discharge to react with the electric field and generates the plasma for the purpose of achieving a good ignition. For example, Japanese Unexamined Patent Application, Publication No. 2011-7155 discloses an internal combustion engine of this type.
The internal combustion engine disclosed in Japanese Unexamined Patent Application, Publication No. 2011-7155 creates an electric field by means of a microwave and allows the electric field to react with a spark discharge. The spark discharge by an ignition plug turns into plasma in the electric field. A flame kernel, which serves as a trigger of flame propagation combustion, is enlarged in comparison with an ignition by a spark discharge alone.